The overall objective of the proposed research program is to throw more light on the molecular and physiological interrelationships between the ionic environment, stimulus-receptor interaction and phospholipid and phosphoprotein phosphate turnover at the neuromuscular junction of the iris smooth muscle. The effects of changes in the ionic environment (e.g., Ca2 ion, Na ion, K ion) in the absence and presence of neurotransmitters, e.g., acetylcholine and norepinephrine, and pharmacological agents on phospholipid and phosphoprotein phosphate turnover will be investigated. Methodology for the studies on the individual phosphoproteins of the iris will be developed. A special effort will be made to investigate the phosphoinositide effect in the sphincter, dilator and ciliary body of the iris-ciliary body. Kinetic properties of the enzymes Na ion-K ion-ATPase and Ca2 ion-ATPase in these muscles will also be studied. It is hoped that the above proposed studies will give us information on the interrelationships between receptor activation, phosphoinositide metabolism and cationic transport processes.